We consider a two-period model where a durable-goods monopolist might engage in "dynamic obsolescence" by changing the durability of the good in period 2 from what was planned in period 1 (e.g. through software updates) after consumers have bought it. We show that given the opportunity to do so, in the subgame perfect Nash equilibrium of the game the monopolist chooses to reduce the durability in the second period. Moreover, we show that if the monopolist commits to a durability level (i.e. use planned obsolescence), then he achieves a higher profit compared to the case of dynamic adjustment of durability.

We study a multiple-receiver Bayesian persuasion model in which the sender wants to persuade a critical mass of receivers. Receivers are connected in a network and can perfectly observe their immediate neighbors' signals, which complicates the problem of the sender. We simplify the problem by considering signaling schemes ("experiments") in which certain receivers are never targeted, effectively dividing the network and preventing some of the information spillovers. Using this divided network approach, we derive lower bounds on the value of the sender, find experiments that achieve them, and provide sufficient conditions for the lower bounds to coincide with the optimal value. Our approach is robust to adding and severing some connections, sometimes even when adding more connections than existing in the original network. Finally, we demonstrate how our approach can be implemented if the network is non-divisible (e.g., a star) and compute the lower bound for such cases. This allows us to better interpret cultural phenomena such as echo chambers and opinion polarization.

We study a Bayesian persuasion setting in which a sender wants to persuade a critical mass of receivers by revealing partial information about the state to them. The homogeneous binary-action receivers are located on a communication network, and each observes the private messages sent to them and their immediate neighbors. We examine how the sender's expected utility varies with increased communication among receivers. We show that for general families of networks, extending the network can strictly benefit the sender. Thus, the sender's gain from persuasion is not monotonic in network density. Moreover, many network extensions can achieve the upper bound on the sender's expected utility among all networks, which corresponds to the payoff in an empty network. This is the case in networks reflecting a clear informational hierarchy (e.g., in global corporations), as well as in decentralized networks in which information originates from multiple sources (e.g., influencers in social media). Finally, we show that a slight modification to the structure of some of these networks precludes the possibility of such beneficial extensions. Overall, our results caution against presuming that more communication necessarily leads to better collective outcomes. 

(Different versions of some results in this paper have previously appeared under the titles Pitfalls of Information Spillovers in Persuasion and Persuading Communicating Voters, which received Best Paper Award - Gold position at GamesNet Young Scholars' Competition; see also https://www.youtube.com/watch?v=tFqe2F931LE - prepared for TARK XVIII)